Infectious Diseases: Some Recent Threats

摘要

Historically, travel around the world was slow; but once infectious diseases were transmitted, the results were often devastating. For example, during the 16th century the Spanish invaded parts of Central and South America. The natives there had no resistance to European diseases like smallpox and measles. As a result, within half a century the Mexican population was reduced from more than 30 million to less than 3 million because of these diseases.